Hi,
These things are the dog's bo***cks! I use the second type below all the time when travelling.
http://cgi.ebay.co.uk/Targus-Univers...QQcmdZViewItem
or if you want one with air/auto capability then try this one:
http://cgi.ebay.co.uk/Targus-Power-a...QQcmdZViewItem
Just check compatability with your computer on the Targus website but they are pretty universal. There are a few more for sale on eBay. Good luck.